Technical Field
The instant disclosure relates to an earphone, and more particularly, to an earphone having a low frequency driver and a high frequency driver disposed therein. A sound output direction of the low frequency driver is opposite to that of the high frequency driver. Sound waves produced by the low frequency driver are inversed to a sound output opening by a passive diaphragm.
Related Art
Because of the limitation of space, a conventional earphone is usually driven by single speaker driver to produce sound. The conventional design is beneficial to have the overall size of the earphone be thin, compact, and light to meet the requirements of in-ear headphones and ear-hugging headphones. However, a speaker driver usually has well performance on frequency response in a certain frequency range, but not that well in other frequency ranges. Generally, the certain frequency range that performed well by the speaker driver usually pertains to middle and low frequencies, and the frequency range that underperformed usually pertains to high frequency.
Therefore, a kind of earphones has been provided to improve performance of frequency response and resolution of sound. The earphone includes plural speaker drivers respectively suited with different frequency ranges. However, the distances between the speaker drivers and a sound output opening of the earphone are almost the same since the space in the earphone is limited. The response of human auditory sense varies with different frequencies of sound. For example, in the circumstance that the distances between the drivers and the eardrum of a user are the same, the user experiences strong and detailed effect regarding low frequency sound but less resolution regarding high frequency sound. In order to improve the experience of human auditory sense, two ways has been provided. One way is to change driving fashion of the earphone (e.g., lowering the volume of low frequency sound waves), and the other way is to increase the number of washers in the earphone to change the positions of the drivers. Either way drifts off the intention that the plural speaker drivers are adopted for, and requires more accommodating space. Therefore, a new kind of earphone capable of improving frequency response without changing the whole structure is needed.